The present invention relates to a magnetic vacuum circuit breaker with a simple structure which transfers motion to open a power circuit by means of a linkage when the circuit is converted into the state of overload or short-circuit.
In conventional electrical switches, especially those used in power circuits, the contacts are exposed to air, whether the contacts are of the knife or magnetic type. These kinds of switches are unsuitable for use in dusty, moist, easily explosive or combustible environments. Several different types of switches for preventing explosions have been developed, such as oil switches, safety switches, and so forth. However, due to the complex structures of these switches, they are unpractical from a manufacturing standpoint. Accordingly, I disclosed an automatic magnetic switch in the U.S. Pat. application Ser. No. 967,712 filed on Dec. 8, 1978, which issued as U.S. Pat. No. 4,288,767. Although the automatic magnetic switch is simpler than the conventional switches in structure, it automatically opens a power circuit when the power circuit is converted into the state of overload or short-circuit by the complicated motion from a protection means 7 through a magnetic control means 10 to a magnetic contacting plate means 8, as shown in FIG. 1. It is thus desirable to further simplify the structure of the automatic magnetic switch.